This invention relates generally to optical devices for improving visual acuity, and more specifically to a telescope system integrated into a spectacle lens.
Magnification is useful for individuals who have resolution loss due to defects in the optics of the eye or of the retina, specifically of the fovea (i.e., the central part of the retina) which provides detail vision for reading, facial recognition and other fine discrimination tasks. Bioptic telescope systems have been prescribed for use by the visually impaired for many years. These multi-element devices provide magnified images of objects at further distances as compared to single element lenses that can only provide magnification at very close working distances.
Typically, bioptic telescopes are mounted toward the top of a pair of eyeglasses frames with the telescope eyepiece positioned directly above the pupil of the wearer""s eye. This positioning allows the wearer to look under the eyepiece using their unaided vision, and to tip their head downward to sight through the telescope eyepiece to see the magnified image. Bioptic telescopes are available in small, compact Galilean designs that provide narrow fields of view (e.g., about 5 degrees in a 3.0xc3x97 magnifier) and generally provide relatively dim images. Alternative bioptic telescopes are available in large, heavy Keplerian designs that provide brighter images and fields of view at least twice as wide (e.g., 12 degrees in a 4.0xc3x97 magnifier) as Galilean designs. Bioptic telescopes are typically mounted through a spectacle (carrier) lens by drilling a hole through it.
Although these types of visual aids can be effectively used in a variety of settings, a large number of visually impaired people reject them. The obvious and unsightly appearance of these prosthetic devices has been identified as one major reason for the reluctance of the visually impaired to use bioptic telescopes.
Previous attempts to improve the cosmetic appearance of bioptic telescopes include the use of very small Galilean telescopes, small mostly behind-the-spectacle-lens Keplerian telescopes, and horizontal telescopes folded above the spectacle lenses. While each of these devices improves the cosmetics of bioptic telescopes, they remain obtrusive and continue to be generally rejected. In addition, conventional attempts at minimization invariably result in optical compromises such as reductions in field-of-view or image brightness, or both.
Low magnification telescopes can be created by combining a high negative power contact lens or intra-ocular (i.e., surgically implanted) lens with a high positive power spectacle lens. While such telescopes are limited in magnification and severely restrict the field-of-fixation they offer an advantage in cosmetic appearance. However, patients also reject these devices due to the unsightly appearance of the high power spectacle lens. A fully implanted intra-ocular telescopic lens is available. It offers the potential of normally looking spectacles and eyes at the cost of a serious surgical procedure, severely reduced field-of-view (but wide open field-of-fixation), dim image, and possible difficulties with future eye care.
What is needed is a low vision bioptic telescope that provides a relatively wide field-of-view, high-magnification, and a bright-image while being cosmetically appealing and permitting the wearer""s eye to appear natural.
The invention relates to bioptic telescopes for increasing visual acuity. In one embodiment, the illustrative telescope includes a vision lens having a vision axis and a first surface for placement substantially in front of an eye of a user. In alternative embodiments, the vision lens can be a carrier lens or a spectacle lens. The telescope further includes a plurality of optical elements defining an optical path for viewing an object in front of the first surface of the vision lens. Additionally, at least one of the plurality of optical elements is positioned such that at least a portion of the optical path is located within the vision lens in a plane substantially orthogonal to the vision axis. In another embodiment, the vision lens further includes a second surface and at least one of the plurality of optical elements is positioned substantially between the first surface and the second surface of the vision lens.
In one embodiment, the user""s eye simultaneously views the object through the vision lens and the plurality of optical elements. In another embodiment, the vision lens is a spectacle lens. The telescope further includes an eyeglass frame adapted to retain the spectacle lens. In another embodiment, at least a portion of one of the plurality of optical elements is embedded in the vision lens. In alternative embodiments, at least one of the plurality of optical elements is a lens, a mirror, or a holographic element.
In one embodiment, the plurality of optical elements includes an objective lens, an ocular lens, and a plurality of planar mirrors, the plurality of planar mirrors is adapted to direct the optical path between the objective lens and the ocular lens. The telescope can be a Galilean or Keplerian type telescope. In another embodiment, at least one of the plurality of planar mirrors is located completely within the lens.
The invention is further related to a vision enhancing system. The vision enhancing system includes a spectacle lens having a vision axis and a first surface for placement substantially in front of an eye of a user. The system further includes a telescope in communication with the spectacle lens for viewing an object in front of the first surface of the spectacle lens. The telescope includes an objective lens having an objective lens axis which is substantially parallel to the vision axis. The telescope further includes an ocular lens in optical communication with the objective lens and having an ocular lens axis which is substantially parallel to the vision axis. The telescope further includes a plurality of optical elements defining an optical path between the objective lens and the ocular lens. At least one of the plurality of optical elements is positioned such that at least a portion of the optical path is located within the spectacle lens in a plane substantially orthogonal to the vision axis.
In one embodiment, the spectacle lens further includes a second surface and at least one of the plurality of optical elements is positioned substantially between the first surface and the second surface of the spectacle lens. In another embodiment, the user""s eye simultaneously views the object through the spectacle lens and the telescope. In yet another embodiment, an eyeglass frame is adapted to retain the spectacle lens. In still another embodiment, at least a portion of one of the plurality of optical elements is embedded in the spectacle lens. In yet another embodiment the telescope is either a Galilean or Keplerian type telescope.
The invention also relates to a method for constructing a telescope. The method includes the steps of mounting a lens having a vision axis and including a first surface to a frame such that the lens is positioned substantially in front of an eye of a user. The method further includes the step of arranging a plurality of optical elements relative to the lens, such that the plurality of optical elements defines an optical path for viewing an object in front of the first surface. At least one of the plurality of optical elements is positioned such that at least a portion of the optical path is located within the lens in a plane substantially orthogonal to the vision axis. In another embodiment, the step of arranging the plurality of optical elements includes placing an objective lens in optical communication with the lens. In another embodiment, the step of arranging the plurality of optical elements includes placing an ocular lens in optical communication with the lens.